Truck-trailer transit mixer



Nov. 26, 1963 E. s. PRICHARD TRUCK-TRAILER TRANSIT MIXER 4 Sheets-Sheet1 Filed May 31, 1962 INVENTOR. 51 44 5. Pele/#720 M ifdam/ flrroewsys.

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TRUCK-TRAILER TRANSIT MIXER Filed May 31, 1962 4 Sheets-Sheet 3INVENTOR.

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K/W r i/m! United States Patent 3,112,100 TRUCK-TRAILER TRANSIT MIXEREvan S. Prichard, Newport Beach, Calif, assignor t0 Challenge-CookBros., Incorporated, Los Angeles, Calif., a corporation of CaliforniaFiled May 31, 1962, Ser. No. 199,090 19 Claims. (Cl. 259-161) Thisinvention relates to a transit mixer for mixing aggregate materials intransit from a bulk-loading plant to a job site, and more particularlyto the combination of a truck with a wheeled truck body frame extensionor semi-trailer (hereinafter, for purposes of convenience, sometimesreferred to simply as a trailer), which combines many of the advantagesof a truck transit mixer with those of a motor vehicle trailer, so as toobtain greater pay-load capacity without sacrifice of maneuverability,and so as to provide increased wheel length and better axle weight-loaddistribution.

In addition to providing increased axle-weight-load distribution,whereas transit mixers generally in use have loading and dischargemechanisms permanently mounted adjacent the open loading and dischargeend of their mixer drums, the device of the present invention may alsoprovide a means for removing its loading and discharge mechanism fromthe vicinity of the open end of the drum, so that the aggregate mix inthe drum may be more readily inspected and sampled, prior to dischargefrom the drum; so that the interior of the drum may be more easily andeffectively cleaned after cargo discharge; and so that the loading anddischarge mechanism itself may be more readily available for cleaning.

Generally speaking, a transit mix truck is more maneuverable than atransit mix truck-trailer combination having the transit mix drummounted solely on the trailer, and loading and discharge of cargo isnormally more readily accomplished with a truck than with a trucktrailercombination. However, due principally to motor vehicle highwayrestrictions, but also due to problems of proper transit weightdistribution, the carrying capacity of the transit mix drum of a truckis restricted, and payload is limited.

It is therefore an object of the present invention to provide a transitmixer having the maneuverability advantages of a transit mixer truck,but also having increased wheel length and improved weight distributioncharacteristics during transit provided by the unique trailer of thedevice, so that a drum of larger capacity may be utilized, andconsequently, so that a larger pay-load may be carried.

It is another object of the invention to provide a transit mixer inwhich part of the overall weight is borne by the truck body frameextension or semi-trailer axle and wheels during transit, but in whichthe trailer is movable out of following position during loading anddischarge operation so as not to interfere with effective loading anddischarge.

It is still another object of the invention to provide such a transitmixer in which the loading and discharge mechanism is carried by thetrailer, so that during transit the weight of such mechanism is borne bythe axle and wheels of the trailer, rather than by the truck, but uponcargo loading or discharge, the loading and discharge mechanism isbrought into operative position at the open end of the drum by pivotalmovement of the trailer upwardly from its extended transit position.

It is yet another object of the invention to provide a truck-trailercombination which has the turning radius characteristics of a truck,rather than those of the usual truck-trailer combination.

With these and other objects in View, the invention consists of theconstruction, arrangement and combinaice tion of the various parts ofthe device whereby the objects contemplated are attained, as hereinafterset forth, pointed out in the appended claims, and illustrated in theaccompanying drawings.

In the drawings:

FIGURE 1 is a side elevational view of the device of the presentinvention in transit position.

FIGURE 2 is a view similar to FIGURE 1, but with the device in loadingand discharge position.

FIGURE 3 is an illustrative plan view showing the turning radiuscharacteristics of the device of the present invention.

FIGURE 4 is an enlarged, fragmentary, detailed side elevational view ofthe rear end of the device in transit position.

FIGURE 5 is a view similar to FIGURE 4, but with the device in loadingand discharge position.

FIGURE 6 is a rear elevational view of the device of the presentinvention in the transit position shown in FIGURE 4.

FIGURE 7 is a view similar to FIGURE 6, but with the device in theloading and discharge position shown in FIGURE 5.

FIGURE 8 is a diagrammatic illustration of the hydraulic loaddistributing, shock absorbing, and trailer retracting means of theinvention.

FIGURE 9 is a bottom plan view of a first alternative form ofconstruction of the ground contacting wheel assembly for the truck bodyframe extension or semi-trailer of the device of the present invention.

FIGURE 10 is a rear elevational view of the wheel assembly illustratedin FIGURE 9.

FIGURE 11 is a side elevational view of the wheel assembly illustratedin FIGURES 9 and 10.

FIGURE 12 is a view similar to FIGURE 9, but showing a secondalternative form of construction of said wheel assembly.

As illustrated in the drawings, a truck, generally designated as 10, hasa body frame 11 having a forward end 12 and a rear end 13. Steeringwheels 14 are mounted forwardly, adjacent forward end 12, on a steeringaxle '15; and truck rear wheels 16, which may be standard tandem rearwheels, as illustrated in the drawings, are mounted rearwardly, adjacentrear end 13, on axles 17. An operators cab 18 is mounted forwardly onbody frame 11.

A trailer, generally designated as 20, has a frame 22 having a forwardend 24 and a rear end 26. Frame 22 of trailer 20 is pivotally mounted atits forward end 24 to body frame 11 of truck '10 adjacent rear end 13 offrame 11. Pivotal mounting of frame 212 to frame 11 may be accomplishedby providing a pair of aligned trunnions 27 mounted on opposite sides offrame 11 and extending below frame 11, with a cross-bar 28 rotatablymounted between said trunnions 27 and below said frame 11, forward end24 of frame 22 being mount ed on and supported by said bar 28.

Trailer frame 22 is comprised of a first pair of substantially parallelarms 30 which, when the device is in the transit position illustrated inFIGURES 1 and 4, are rearwardly extending and upwardly inclined; asecond pair of substantially parallel, rearwardly extending, butdownwardly inclined arms 32, which are integrally formed with said arms30 to form an obtuse angle therebetween; a third pair of arms 34,rearwardly extending in converging relationship toward each other andslightly upwardly inclined, which are integrally formed with said arms32; a fourth pair of substantially parallel arms 36, rearwardlyextending and substantially parallel to the ground (designated 37) whichare integrally formed with said third pair of arms 34; and a rear crossmember 38, which joins said fourth pair of arms 36.

A cross-beam 40 extends transversely between arms 36 adjacent rear crossmember 38. A swivel pin 42 is centrally mounted on cross-beam 40adjacent the upper end 44 of said pin 42, said pin 42 extendingvertically downwardly from trailer 20 when trailer 20 is in transitposition. At the lower end 46 of pin 42 a transverse axle 48 is mountedat substantially the center of said axle 48. A pair of trailer wheels 50is mounted on said axle 48 and disposed on opposite sides of said pin42. If desired, said wheels 50 may be equipped with mud guards 52 andsplash guards 54.

Rotatably mounted on frame 11 of truck is a mixer drum 60 which has aforwardly disposed closed end 62 and a rearwardly disposed, upwardlyinclined open end 64 adapted to receive and discharge cargo. In themanner which has become standard in the transit mixer industry, drum 60is rotatably supported on truck frame 11 at its forward closed end 62 bya drive mechanism, generally illustrated in FIGURES 1 and 2 of thedrawings and designated 65 (no particular claim being made to thedetails of the drive mechanism employed). Drum 60 is rearwardlysupported on truck frame 11, also in a manner which has become standardin the industry, as by a pair of stanchions 66 which support rollers(not illustrated), which rollers in turn bear on a ring 67 mountedexternally on drum 60 adjacent open end 64.

Open end 64 is disposed adjacent the vertical plane of rear end 13 oftruck frame 11 so that it will be readily available for loading anddischarge of cargo.

When it is desired to carry the loading and discharge mechanism on thetruck body frame extension or trailer 20, as illustrated in thedrawings, there are mounted on and supported by trailer a loading hopper70, a discharge accumulator 80, and a discharge chute 90, said hopper70, accumulator 80 and chute 90 being disposed on said trailer 20 sothat, when the rig is in transit, as best illustrated in FIGURES l, 4and 6 of the drawings, said hopper, accumulator and chute extendgenerally rearwardly from frame 11 of truck 10, but when loading ordischarge of cargo is to be accomplished, as best illustrated in FIGURES2, 5 and 7 of the drawings, said hopper, accumulator and chute are movedby the elevated pivoting of trailer 20 to operating position closelyadjacent to the open end of the mixer drum, in the manner hereinafterdescribed in more detail.

Hopper 70 is mounted rearwardly on trailer 20 above arms 36 by anysuitable means, such as by support bracket 72 mounted on rear member 38and on hopper 70, and by a pair of brackets 74, preferably of inverted Yconfiguration, mounted on hopper 70 adjacent open loading end 75 ofhopper 70 and on arms 32. Said hopper 70 has a loading chute 76 formedthereon, said hopper 70 and loading chute 76 being positioned on trailer20 so that, when trailer 20 is swung upwardly to loading and dischargeposition, hopper 70 will be substantially vertically disposed adjacentopen end 64 of drum 60, with open end 75 of hopper 70 somewhat aboveopen end 64 of drum 60, and with loading chute 76 projecting into openend 64 of drum 60 so that the aggregate cargo can be easily disposed indrum 60.

Discharge accumulator 80 is mounted on trailer 20 adjacent hopper 70 andis disposed between arms 34 and arms 32. Accumulator 80 may be mountedon trailer 20 by any suitable means, such as by disposing its upper end82 in a ring 84 and mounting said ring 84 on brackets 74 andadditionally, if desired, mounting it on arms 34 as at 85. Accumulator80 may have external annular rings 86, spaced apart from each otheradjacent lower open end 87, the space between said rings 86 serving as atrack for trolleys 88 to which the upper end 92 of discharge chute 90 ispivotally attached.

Intermediate the upper end 92 and the lower end 93 of discharge chute 90is a pivotal mounting 94. A hydraulic cylinder 95 is pivotally mountedadjacent the rear end 13 of frame 11 of truck 10, and a piston rod 96protrudes from cylinder and has its free end attached to chute 90 atsaid pivotal mounting 94.

A trunnion 100 is mounted on a cross-beam 101 between arms 30 of trailer20 intermediate the ends of said arms 30. A trunnion 102 is mounted onbody frame 11 of truck 10 adjacent the rear end 13 of frame 11. Ahydraulic cylinder 104 is pivotally mounted at one end 105 thereof tosaid trunnion 102. A piston 106 is slidably disposed in cylinder 104,and a piston rod 107 is mounted on piston 106 and projects from theopposite end 108 of cylinder 104, and the free end of said piston rod107 is pivotally connected to said trunnion 100.

As illustrated in FIGURE 8 of the drawings, a hydraulic fluid pump isprovided. A first hydraulic fluid pressure line 122 leads from pump 120to a tank reservoir 124. A second hydraulic fluid pressure line 126leads from reservoir 124 to a hydraulic fluid directional control valve128. A third hydraulic fluid pressure line 130 leads from pump 120 tovalve 128. A fourth hydraulic fluid presure line 132 leads from valve128 to a first port 134 in cylinder 104, said first port 134 beingdisposed adjacent to end 105 of cylinder 104, and between piston 106 andsaid end 105 so as to provide hydraulic fluid access to the interior ofcylinder 104 in that area. A fifth hydraulic fluid pressure line 136leads from valve 128 to a second port 138 in cylinder 104, said secondport 138 being disposed adjacent to end 108 of cylinder 104, and betweenpiston 106 and said end 108 so as to provide hydraulic fluid access tothe interior of cylinder 104 in that area.

A hydraulic accumulator 140 may be provided. Said accumulator 140contains a gaseous element 142, and a sixth hydraulic fluid pressureline 144 leads from accumulator 140 to a third port 146 in cylinder 104,said third port 146 being disposed, similar to first port 134, adjacentto end 105 of cylinder 104, and between piston 106 and said end 105.

In the alternative forms of construction of the truck body frameextension or semi-trailer illustrated in FIG- URES 9-12, inclusive, ofthe drawings, in lieu of swivel pin 42, a vertically, downwardlydirected, fixed pin 200 is centrally mounted on cross-beam 40, oralternatively, is mounted on a frame 202, in turn mounted on crossbeam40 and extending downwardly therefrom. An axle 204 is transverselymounted at the lower end of pin 200 at substantially the center of saidaxle 204. Standard steering wheel king pins 206 are provided at the endsof axle 204, and wheels 208 are suitably mounted on king pins 206. Tiearms 208 are connected to said king pins 206 and said wheel mountings,and a tie rod 210 connects said tie arms 208, so that a standardsteering wheel assembly is provided, and said wheels 208 will turn as aunit.

In the second alternative form of the device illustrated in FIGURE 12 ofthe drawings, a standard hydraulic steering mechanism 220 may be mountedon tie arms 208. Although not illustrated in the drawings, it will bereadily understood that said hydraulic steering mechanism may beoperated by a steering wheel accessibly mounted on trailer 20, or may beconnected by hydraulic fluid pressure lines to the normal hydraulicsteering mechanism of truck 10, so that hydraulic steering by the driverof steering wheels 14 will also provide hydraulic steering by him ofWheels 208.

When the transit mixer is in transit, piston rod 107 is extended, byhydraulic pressure in cylinder 104, between end 105 of cylinder 104 andpiston 106, so that trailer 20 is in following position behind truck 10,and the trailer wheels are in contact with the ground 37, and theweightload is distributed over the entire combination of truck frame 11and trailer 20. As the trailer mixer progresses along its way, by theaction of hydraulic accumulator 140, piston rod 107 will be eitherfurther extended or retracted, as ground pressure on wheels 50 decreasesor increases, so that wheels 50 will follow the varying contours of theground 37 (spring action and shock absorbing of trailer 20 being thuseffectively provided, and weight-load distribution is maintained).

Operation of pump 120 and adjustment of valve 128 will permit highpressure hydraulic fluid to flow into cylinder 104 between end 105 andpiston 106, to move piston 106 toward end 108 of cylinder 104, and thusto extend piston rod 107 to bring the trailer wheels into groundcontact, and maintain them in ground contact, variations in groundpressure being compensated for by accumulator 140.

Additionally, when the transit mixer is in the position illustrated inFIGURES l, 4 and 6 of the drawings, open end 64 of drum 60 will be clearof impediments, and accessibly open to view, so that, if drum 60 isloaded with cargo, the aggregate mix in drum 60 may be readily, visuallyinspected, tested, or sampled, to determine, for instance, the slump ofthe cargo, without the normal requirement of cargo discharge beforeadequate slump tests may be performed. Furthermore, if drum 60, in thatposition of the transit mixer, is empty of cargo, ready access to openend 64 will permit easy cleaning of the interior of drum 60, as by ahose. Similarly, because under these conditions, hopper 70, dischargeaccumulator 80, and discharge chute 90, mounted as they are on trailer20, are accessibly positioned relatively close to the ground 37 and awayfrom other obstructions, they may be readily cleaned, say, by a manstanding on the ground 37 and equipped with a hose.

When drum 60 is to be loaded or discharged, further adjustment of valve128 will permit high pressure hydraulic fluid to flow into cylinder 104between end 108 and piston 106, to move piston 106 toward end 105 ofcylinder 104, and thus retract piston rod 107 so as to cause trailer 20to pivot on body frame 11 and swing upwardly, until hopper 70 anddischarge accumulator 80 are in proper operative position adjacent openend 64 of drum 60. If discharge is to be accomplished, discharge chute90 will then be positioned relative to discharge accumulator 80, byoperation of cylinder 95, to direct discharged cargo in any desireddirection.

Because in the first form of the device, axle 48 is transversely mountedon swivel pin 42, and because trailer 20 is connected to body frame 11of truck for pivotal elevation, but not for lateral movement relative toframe 11, when steering wheels 14 are turned, the entire transit mixerwill turn in the radius illustrated in FIGURE 3 of the drawings, andtrailer will not separately follow a wider radius of turn.

Similarly, in the alternative forms of the wheel assembly of the trailerillustrated in FIGURES 9-12, inclusive, of the drawings, the radius ofturn of the device will be similarly controlled.

Although the invention has been herein shown and described in what areconceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention, which is not to be limited to the details disclosed herein,but is to be accorded the full scope of the claims so as to embrace anyand all equivalent structures and devices.

What is claimed is:

l. A transit mixer which comprises: a truck; a rotatable mixer drummounted on said truck, said drum having an open cargo loading anddischarge end disposed rearwardly on said truck; a trailer pivotallymounted on said truck; and elevatable means mounted on said trailer forloading cargo into said drum and discharging cargo from said drum, saidmeans being adapted to be elevated and brought into close proximity tothe open end of said drum by upward swinging of said trailer duringloading and discharge operations.

2. A transit mixer as defined in claim 1, including a hydraulic cylinderand piston assembly mounted on said truck and connected to said trailerso as to maintain weight distribution over said truck and said trailer,so

as to maintain said trailer in contact with the ground during transit,and so as to swing said trailer upwardly for loading and discharge ofcargo into and out of said drum.

3. A transit mixer as defined in claim 1, wherein said trailercomprises: a first pair of substantially parallel arms pivotally mountedon said truck, extending rearwardly therefrom and upwardly inclined; asecond pair of substantially parallel, rearwardly extending anddownwardly inclined arms integrally formed with said first pair of armsat an obtuse angle; a third pair of arms extending rearwardly inconverging relationship to each other, upwardly inclined and integrallyformed with said second pair of arms; and a fourth pair of substantiallyparallel arms integrally formed with said third pair of arms andextending rearwardly therefrom substantially parallel to the ground whenthe transit mixer is in transit position.

4. A transit mixer as defined in claim 3, including a downwardlydirected pin supported by said fourth pair of arms; an axle transverselymounted on said pin; and ground-contacting wheels mounted on said axleso as to support the rear of said trailer.

5. A transit mixer which comprises: a truck having forward steeringwheels mounted on a forward axle, and rear ground contacting wheelsmounted on rear axles; a rotatable mixer drum mounted on said truck,said drum having an open end disposed rearwardly on said truck adjacentthe vertical plane of the rear of said truck; a trailer pivotallymounted at the rear of said truck; a pin mounted on and depending fromsaid trailer; a transverse axle mounted on said pin; a pair of wheelsmounted on said axle so as to support said trailer on the ground duringtransit; and elev-atable means mounted on said trailer for loading cargointo said drum and discharging cargo from said drum, said means beingadapted to be elevated clear of the ground and brought into closeproximity to the open end of said drum by upward swinging of saidtrailer during loading and discharge operations.

6. A transit mixer as defined in claim 5, wherein said means for loadingcargo into and discharging cargo from said drum comprises: a loadinghopper mounted rearwardly on said trailer; a loading chute mounted onsaid loading hopper so as to be disposed in the open end of said drumwhen said trailer is swung upwardly; a discharge accumulator mountedforwardly of said hopper so as to be disposed closely adjacent to theopen end of said drum, below said hopper, when said trailer is swungupwardly; and a discharge chute adjustably mounted forwardly of saidaccumulator so as to be disposed in cargo discharge position adjacent toand below said accumulator when said trailer is swung upwardly.

7. A transit mixer as defined in claim 6, including a hydraulic cylinderpivotally mounted at one end thereof to said truck adjacent the rear endof said truck; and a piston rod protruding from said cylinder, the freeend of said piston rod being pivotally connected to said trailer, sothat, upon actuation of said cylinder in one direction, said piston rodwill be extended to provide weight distribution over said truck axlesand said trailer axle, and to maintain said trailer in extended, groundcontacting position behind said truck, and upon actuation of saidcylinder in the other direction, said piston rod will be retracted toswing said trailer upwardly and bring said hopper, loading chute,accumulator, and discharge chute, into elevated operative positionadjacent the open end of said drum.

8. A transit mixer which comprises: a truck having a body frame;steering wheels mounted forwardly on said body frame; ground-contactingwheels mounted rearwardly on said body frame; a rearwardly disposed andrearwardly, upwardly inclined, rotatable mixer drum mounted on saidtruck, said :drum having an elevated open end disposed adjacent thevertical plane of the rear of said body frame; a trailer pivotallymounted on said body frame at the rear of said body frame; a swivel pinmounted on and depending from said trailer; a transverse axle mounted onsaid swivel pin; a pair of wheels mounted on said axle and adapted tocontact the ground when said transit mixer is in transit position; meansmounted on said trailer for loading cargo into said drum and dischargingcargo from said drum through the open end of said drum; and meansmounted on said body frame and on said trailer for pivotally elevatingsaid trailer and for bringing said loading and discharge means intoclose proximity to the open end of said drum for loading cargo into anddischarging cargo from said drum.

9. A transit mixer as defined in claim 8, wherein said means for loadingcargo into and discharging cargo from said drum comprises: a loadinghopper mounted rearwardly on said trailer; a loading chute mounted onsaid loading hopper so as to be disposed in the open end of said drumwhen said trailer is pivotally elevated; a discharge accumulator mountedforwardly of said hopper so as to be disposed closely adjacent to theopen end of said drum, below said hopper, when said trailer is pivotallyelevated; and a discharge chute adjustably mounted forwardly of saidaccumulator so as to be disposed in cargo discharge position adjacent toand below said accumulator when said trailer is pivotally elevated.

10. A transit mixer as defined in claim 9, wherein the means forpivotally elevating said trailer and bringing said loading and dischargemeans into close proximity to the open end of said drum comprises: ahydraulic cylinder pivotally mounted at one end thereof to said bodyframe adjacent the rear end of said body frame; and a piston rodprotruding from said cylinder, the free end of said piston rod beingpivotally connected to said trailer, so that, upon actuation of saidcylinder in one direction, said piston rod will be retracted to swingsaid trailer upwardly and bring said hopper, loading chute, accumulator,and discharge chute, into elevated position adjacent the open end ofsaid drum.

11. A transit mixer as defined in claim 10, including means pivotallymounted on said body frame and on said discharge chute for adjustablydisposing said discharge chute in relation to said dischargeaccumulator.

12. A transit mixer as defined in claim 11, wherein said means foradjustably disposing said discharge chute comprises a hydraulic cylinderand piston rod assembly.

13. A transit mixer which comprises: a truck having a body frame;steering wheels mounted forwardly on said body frame; ground contactingwheels mounted rearwardly on said body frame; a rearwardly disposed andrearwardly, upwardly inclined, rotatable mixer drum mounted on saidtruck, said drum having an elevated open end disposed adjacent thevertical plane of the rear of said body frame; a trailer pivotallymounted on said body frame at the rear of said body frame; a pin mountedon and depending from said trailer; a transverse axle mounted on saidpin; a pair of trailer wheels mounted on said axle; means mounted onsaid body frame and on said trailer for maintaining said trailer wheelsin contact with the ground when said transit mixer is in transitposition; means mounted on said trailer for loading cargo into said drumand discharging cargo from said drum through the open end of said drum;and means mounted on said body frame and on said trailer for pivotallyelevating said trailer and for bringing said loading and discharge meansinto close proximity to the open end of said drum for loading cargo intoand discharging cargo from said drum.

14. A transit mixer as defined in claim 13, wherein the means formaintaining said trailer wheels in contact with the ground duringtransit comprises: a hydraulic cylinder pivotally mounted at one endthereof to said body frame adjacent the rear end of said body frame; apiston slidably disposed in said cylinder; and a piston rod connected tosaid piston and protruding from said cylinder, the free end of saidpiston rod being pivotally connected to said trailer, so that, uponactuation of said cylinder in one direction, said piston rod will beextended to maintain said trailer in extended, ground-contactingposition behind said body frame.

15. A transit mixer as defined in claim 14, including a hydraulicaccumulator mounted on said body frame and connected to said hydrauliccylinder so as to cushion the hydraulic action of said cylinder when thetransit mixer is in transit, and maintain contact of the trailer wheelswith the ground regardless of ground grade variations.

16. A transit mixer which comprises: a truck having a body frame;steering wheels mounted forwardly on said body frame; ground-contactingwheels mounted rearwardly on said body frame; a rearwardly disposed andrearwardly, upwardly inclined, rotatable mixer drum mounted on saidtruck, said drum having an elevated open end disposed adjacent thevertical plane of the rear of said body frame; a trailer pivotallymounted on said body frame at the rear of said body frame; a pin mountedon and depending from said trailer; a transverse axle mounted on saidpin; a pair of trailer wheels mounted on said axle; means mounted onsaid trailer for loading cargo into said drum and discharging cargo fromsaid drum through the open end of said drum; and a reciprocal hydrauliccylinder and piston rod assembly pivotally mounted on said body frameand on said trailer for maintaining said trailer wheels in contact withthe ground when the transit mixer is in transit, and for pivotallyelevating said trailer and bringing said loading and discharge meansinto close proximity to the open end of said drum when loading anddischarge of cargo is to be accomplished.

17. A transit mixer as defined in claim 16, wherein said trailer wheelsare steerable.

18. A motor vehicle which comprises: a truck having a body frame,forward steering wheels, and rear ground contacting wheels; a rotatablemixer drum mounted on said truck; a truck body frame extension pivotallymounted on the body frame of said truck rearwardly of the wheels of saidtruck, and extending rearwardly from said truck body frame; groundcontacting wheels mounted on said truck body frame extension anddisposed to turn when the steering wheels of the truck are turned so asto maintain a turning radius for said truck and said body frameextension; and means interconnecting the body frame of said truck andsaid truck body frame extension for elevating said truck body frameextension.

19. A motor vehicle which comprises: a truck having a body frame,forward steering wheels, and rear ground contacting wheels; a rotatablemixer drum mounted on said truck; a truck body frame extension pivotallymounted on the body frame of said truck rearwardly of the wheels of saidtruck, and extending rearwardly from said truck body frame; groundcontacting wheels mounted on said truck body frame extension anddisposed to turn when the steering wheels of the truck are turned so asto maintain a turning radius for said truck and said body frameextension; means inter-connecting the body frame of said truck and saidtruck body frame extension for elevating said truck body frameextension; and a recipro eating hydraulic cylinder and piston assemblypivotally mounted on the truck body frame and on the body frameextension and disposed so as to maintain the body frame extension incontact with the ground during transit and provide weight distributionover said body frame exten sion and said truck.

References Cited in the file of this patent UNITED STATES PATENTS3,019,002 Prichard Jan. 30, 1962 FOREIGN PATENTS 114,850 Australia Mar.6, 1942

1. A TRANSIT MIXER WHICH COMPRISES: A TRUCK; A ROTATABLE MIXER DRUMMOUNTED ON SAID TRUCK, SAID DRUM HAVING AN OPEN CARGO LOADING ANDDISCHARGE END DISPOSED REARWARDLY ON SAID TRUCK; A TRAILER PIVOTALLYMOUNTED ON SAID TRUCK; AND ELEVATABLE MEANS MOUNTED ON SAID TRAILER FORLOADING CARGO INTO SAID DRUM AND DISCHARGING CARGO FROM SAID DRUM, SAIDMEANS BEING ADAPTED TO BE ELEVATED AND BROUGHT INTO CLOSE PROXIMITY TOTHE OPEN END OF SAID DRUM BY UPWARD SWINGING OF SAID TRAILER DURINGLOADING AND DISCHARGE OPERATIONS.